Lighting system utilizing waveguides with extraction feature patterns

ABSTRACT

According to an aspect of the present disclosure, a luminaire comprises a plurality of waveguides, a light source arranged to direct light into the plurality of waveguides, and a plurality of extraction feature patterns. The luminaire contemplated by the present disclosure is arranged with the plurality of waveguides are aligned such that an extraction feature pattern extracts light out of a first waveguide of the plurality of waveguides and a second extraction feature pattern extracts light out of a second waveguide of the plurality of waveguides. Further, in accordance with this aspect, the light extracted out of the first waveguide is directed through the second waveguide to develop an appearance of depth.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. Pat. No. 10,859,753,which is a continuation-in-part of U.S. patent application Ser. No.15/419,538, filed Jan. 30, 2017 and subsequently issued as U.S. Pat. No.10,502,374; and claims the benefit of U.S. Provisional PatentApplication Ser. No. 62/628,131, filed Feb. 8, 2018, wherein the entiredisclosures of the foregoing documents are hereby incorporated byreference herein.

REFERENCE REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable

SEQUENTIAL LISTING

Not applicable

FIELD OF DISCLOSURE

The present subject matter relates to general illumination lighting, andmore particularly, to outdoor, indoor, and/or enclosed structureluminaires usable, for example, in home, office, and/or warehousesettings to produce aesthetically desirable lighting solutions.

BACKGROUND

Large areas of open indoor space, such as an office or warehouse spaces,require sufficient lighting to allow for safe and comfortable activitiesby persons occupying or visiting the space at all times includingperiods when natural lighting, such as that provided by windows, isunavailable or reduced during nighttime, rainy or foggy weatherconditions, and/or in the absence of windows. An indoor luminaire forlarge indoor spaces or smaller indoor spaces, such as hallways orindividual office spaces, must illuminate spaces varying in size, floorplan, and intended use. It may be useful for such a luminaire to providecustomizable illumination patterns in order to effectively match thelight produced by the luminaire with the characteristics of the space tobe illuminated. Still further, such a luminaire should be customizablesuch that desired illumination patterns may be achieved. Additionally,such a luminaire should be aesthetically pleasing, and further,versatile enough to provide illumination patterns suitable for thevaried environments mentioned hereinabove.

Often times, skylights are used to provide natural light (i.e.,daylight) in residential, commercial and other buildings, as well as inother structures. Conventional skylights can pose numerous problems,including water leakage, heat loss, lack of light on overcast or stormydays, difficulty installing, and/or impossibility/impracticality ofinstalling, e.g., location in the first story of a multi-storystructure. In addition, conventional skylights, not unlike other naturallight windows, typically get dirty, streaked and/or smeared, and as aresult there is often a frequent desire (or need) to clean saidconventional skylight. In addition, direct sunlight can sometimesproduce a great deal of glare on work surfaces and other items, e.g.,computer screens, and such glare is typically counterproductive and/orundesirable. Also, direct sunlight (and/or resulting glare) may increaseeye strain. Therefore, a substitute for conventional skylights thatcomprises one or more relatively thin waveguides represents andimprovement in the art.

Advances in light emitting diode (LED) technology have resulted in wideadoption of luminaires that incorporate such devices. While LEDs can beused alone to produce light without the need for supplementary opticaldevices, it has been found that optical modifiers, such as lenses,reflectors, optical waveguides, and combinations thereof, cansignificantly improve illumination distribution for particularapplications.

An optical waveguide mixes and directs light emitted by one or morelight sources, such as one or more LEDs. A typical optical waveguideincludes three main components: one or more coupling elements, one ormore distribution elements, and one or more extraction elements. Thecoupling component(s) direct light into the distribution element(s), andcondition the light to interact with the subsequent components. The oneor more distribution elements control how light flows through thewaveguide and is dependent on the waveguide geometry and material. Theextraction element(s) determine how light is removed by controllingwhere and in what direction the light exits the waveguide.

When designing a coupling optic, the primary considerations are:maximizing the efficiency of light transfer from the source into thewaveguide; controlling the location of light injected into thewaveguide; and controlling the angular distribution of the light in thecoupling optic. One way of controlling the spatial and angular spread ofinjected light is by fitting each source with a dedicated lens. Theselenses can be disposed with an air gap between the lens and the couplingoptic, or may be manufactured from the same piece of material thatdefines the waveguide's distribution element(s). Discrete couplingoptics allow numerous advantages such as higher efficiency coupling,controlled overlap of light flux from the sources, and angular controlof how the injected light interacts with the remaining elements of thewaveguide. Discrete coupling optics use refraction, total internalreflection, and surface or volume scattering to control the distributionof light injected into the waveguide.

After light has been coupled into the waveguide, it must be guided andconditioned to the locations of extraction. The simplest example is afiber-optic cable, which is designed to transport light from one end ofthe cable to another with minimal loss in between. To achieve this,fiber optic cables are only gradually curved and sharp bends in thewaveguide are avoided. In accordance with well-known principles of totalinternal reflectance light traveling through a waveguide is reflectedback into the waveguide from an outer surface thereof, provided that theincident light does not exceed a critical angle with respect to thesurface. Specifically, the light rays continue to travel through thewaveguide until such rays strike an index interface surface at aparticular angle less than an angle measured with respect to a linenormal to the surface point at which the light rays are incident (or,equivalently, until the light rays exceed an angle measured with respectto a line tangent to the surface point at which the light rays areincident) and the light rays escape.

In order for an extraction element to remove light from the waveguide,the light must first contact the feature comprising the element. Byappropriately shaping the waveguide surfaces, one can control the flowof light across the extraction feature(s). Specifically, selecting thespacing, shape, and other characteristic(s) of the extraction featuresaffects the appearance of the waveguide, its resulting distribution, andefficiency.

Low-profile LED-based luminaires have recently been developed thatutilize a string of LED components directed into the edge of awaveguiding element (an “edge-lit” or “edge-coupled” approach). However,such luminaires typically suffer from low efficiency due to lossesinherent in coupling light emitted from a predominantly Lambertianemitting source such as a LED component into the narrow edge of awaveguide plane.

The description provided in the background section should not be assumedto be prior art merely because it is mentioned in or associated with thebackground section. The background section may include information thatdescribes one or more aspects of the subject technology.

SUMMARY

According to an aspect of the present disclosure, a luminaire comprisesa plurality of waveguides, a light source arrange to direct light intothe plurality of waveguides, and a plurality of extraction featurepatterns. The luminaire contemplated by the present disclosure isarranged with the plurality of waveguides are aligned such that anextraction feature pattern extracts light out of a first waveguide ofthe plurality of waveguides and a second extraction feature patternextracts light out of a second waveguide of the plurality of waveguides.Further, in accordance with this aspect, the light extracted out of thefirst waveguide is directed through the second waveguide to develop anappearance of depth.

In another aspect of this disclosure, an optical waveguide comprises awaveguide body, first and second light sources respectively directinglight into the waveguide at first and second coupling portions, andfirst and second extraction feature patterns. Further, in accordancewith this aspect, the first extraction feature pattern extracts a firstspectrum of light from the first coupling portion, and the secondextraction feature pattern extracts a second spectrum of light from thesecond coupling portion.

In another aspect of this disclosure, a lighting system comprises firstand second waveguides aligned along a plane adjacent one another, atleast one light emitting diode associated with each of the first andsecond waveguides for coupling light into the respective first andsecond waveguides, and first and second planar light emitting surfacesof the first and second waveguides. Further, according to this aspect,the light emitting surfaces of the first and second waveguides emitlight in substantially the same direction transverse to the plane, andthe light emitted from the first waveguide traverses the secondwaveguide such that the light appears to have a source depth greaterthan a location of the first waveguide.

Yet another aspect contemplated by the present disclosure is an opticalwaveguide comprising a plurality of extraction features disposed in awaveguide body, at least two LEDs directing light into the waveguidebody, first and second planar surfaces, and first and second waveguideportions. Still further, in accordance with this aspect, the pluralityof extraction features are disposed on the first and second waveguideportions, and the first and second waveguide portions emit at leastfirst and second colors of light.

Other aspects and advantages will become apparent upon consideration ofthe following detailed description and the attached drawings whereinlike numerals designate like structures throughout the specification.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide furtherunderstanding and are incorporated in and constitute a part of thisspecification, illustrate disclosed embodiments and together with thedescription serve to explain the principles of the disclosedembodiments. In the drawings:

FIG. 1 illustrates a luminaire according to the present disclosuredisposed in a ceiling and/or a wall;

FIG. 2 is an isometric exploded view from above illustrating theluminaire of the present disclosure;

FIG. 3 is a side elevational view illustrating the luminaire of thepresent disclosure with a housing therefor omitted;

FIG. 4 is a plan view illustrating a planar surface of a waveguide ofthe luminaire of the present disclosure;

FIGS. 5 and 6 are enlarged views of the planar surface of the waveguideof FIG. 4 illustrating extraction features disposed thereon;

FIG. 7 is a plan view illustrating an extraction feature patterndisposed on a waveguide;

FIG. 8 is an isometric view illustrating another extraction featurepattern disposed on a waveguide;

FIG. 9A is an isometric view illustrating another extraction featurepattern disposed on a waveguide;

FIG. 9B is an isometric view illustrating another extraction featurepattern disposed on a waveguide;

FIG. 10 is a color photograph from above of the waveguide of FIG. 7 litby one or more blue and/or violet LEDs;

FIG. 11 is a color photograph from above of the waveguide of FIG. 8 litby one or more yellow and/or warm white LEDs;

FIG. 12 is a color photograph of the luminaire of the present disclosurecomprising the waveguide depicted in FIG. 10 disposed behind thewaveguide of FIG. 11;

FIG. 13 is another color photograph of the luminaire depicted in FIG.12;

FIG. 14 is another color photograph of the luminaire depicted in FIG.12;

FIG. 15 is a plan view of a mask for fabricating extraction featuresaccording to a pattern;

FIG. 16 is an isometric view of the mask of FIG. 15;

FIG. 17 is a color photograph from above of a waveguide comprisingextraction features fabricated with the mask of FIG. 15 and lit by oneor more yellow and/or warm white LEDs;

FIG. 18 is another color photograph from above and to the side of thewaveguide lit by one or more yellow and/or warm white LEDs of FIG. 17;

FIG. 19 is another color photograph from above and to the side of thewaveguide lit by one or more yellow and/or warm white LEDs of FIG. 17;

FIG. 20 is a plan view of a mask for fabricating extraction featuresaccording to a pattern;

FIG. 21 is a color photograph from above of a waveguide comprisingextraction features fabricated with the mask of FIG. 20 and lit by oneor more yellow and/or warm white LEDs;

FIG. 22 is a color photograph from above of a luminaire comprising thewaveguide depicted in FIG. 10 disposed behind the waveguide depicted inFIG. 21;

FIG. 23 is a plan view of a mask for fabricating extraction featuresaccording to a pattern;

FIG. 24 is a graph of an emission spectrum for a bluish LED for use withembodiments;

FIG. 25 is a graph of the emission spectrum for a white LED for use withembodiments;

FIG. 26 is a graph of the emission spectrum for a bluish LED for usewith embodiments;

FIG. 27 is a graph of the emission spectrum for a greenish LED for usewith embodiments; and

FIG. 28 is a graph of the emission spectrum for a white LED for use withembodiments.

In one or more implementations, not all of the depicted components ineach figure may be required, and one or more implementations may includeadditional components not shown in a figure. Variations in thearrangement and type of the components may be made without departingfrom the scope of the subject disclosure. Additional components,different components, or fewer components may be utilized within thescope of the subject disclosure. Throughout the drawings, identicalreference numbers may designate similar, but not necessarily identical,elements. Use herein of a reference numeral without an index number,where such reference numeral is referred to elsewhere with an indexnumber, may be a general reference to the corresponding plural elements,collectively or individually

DETAILED DESCRIPTION

The detailed description set forth below is intended as a description ofvarious implementations and is not intended to represent the onlyimplementations in which the subject technology may be practiced. Asthose skilled in the art would realize, the described implementationsmay be modified in various different ways, all without departing fromthe scope of the present disclosure. Still further, components andprocesses depicted may be combined, in whole or in part, and/or divided,into one or more different parts, as applicable to fit particularimplementations without departing from the scope of the presentdisclosure. Accordingly, the drawings and description are to be regardedas illustrative in nature and not restrictive.

As shown in the FIGS., disclosed herein are embodiments of luminairesand/or light fixtures for general lighting, task lighting, or the like;more particularly, for illumination of spaces of varying size and floorplan such as a warehouse, office space, hallway, dwelling, or otherspace. Preferably, the illuminated space comprises an indoor space,although the luminaires disclosed herein may be used in otherapplications, such as an outdoor space or in a covered spaced exposed tothe weather.

Referring now to FIG. 1, an example embodiment of a luminaire/lightingsystem 100 according to the present disclosure is illustrated. Theluminaire 100 is configured as a skylight and disposed within a ceiling102 of a space to be illuminated. Example embodiments of the luminaire100 may be disposed within a wall 106. Also in embodiments, theluminaire/lighting system 100 may be disposed in a ceiling and/or wallof a hallway. The luminaire/lighting system 100 may provide, among otherthings, the aesthetic, design, and functional properties of anequivalent conventional skylight that allows natural light into a spaceto be illuminated. The luminaire/lighting system 100 may mimic theappearance and/or effects of a conventional skylight, and/or give an“outdoor” feeling to an indoor space, in some cases even with noexterior light supplied by any windows or doors, and instead using theprinciples of total internal reflection (TIR) and one or more opticalwaveguides 112. Still further, the waveguide bodies contemplated hereinare made of any suitable optically transmissive material, such as anacrylic material, a silicone, a polycarbonate, a glass material, acyclic olefin copolymer, air, or other suitable material(s), orcombinations thereof to achieve a desired effect and/or appearance.

The present disclosure contemplates that the luminaire/lighting system100 may provide an appearance effect 108 (FIG. 12) such as the illusionof depth, perspective, optical illusions, patterns, skylight imitation,and/or another desired optical effect. Still further, theluminaire/lighting system 100 may provide patterns complementary to theilluminated space. In example embodiments, the appearance of theluminaire/lighting system 100 supplies one or more of the aforementioneddesirable effects. Also in example embodiments, the luminaire/lightingsystem 100 may produce one or more desirable illumination effects suchas one or more light distribution and/or illumination patterns in thespace to be illuminated. Still further in example embodiments, thedesirable appearance effect 108 of the luminaire/lighting system 100 maybe directly or indirectly associated with one of the desirableillumination effects.

The present disclosure further contemplates the luminaire/lightingsystem 100 comprising one or more luminaires 100 a, 100 b, . . . 100 n.Each of the luminaires 100 n may produce one or more of the appearanceeffects 108 and/or the illumination effects. Each of the luminaires 100n, in operation together to form a coordinated and/or networked lightingsystem 104, may provide one or more appearance effects 108 and/orillumination effects to develop overall appearance and/or illuminationeffects 108, desirable for the lighting system 104 as a whole. Theluminaire 100 detailed hereinthroughout may be referred tointerchangeably as the luminaire 100, the skylight 100, the fixture 100,the lighting apparatus 100, and/or the lighting device 100; and furthermay comprise one or more light emitting diodes (LEDs) 130 and/or anothersuitable light source (such as a fluorescent bulb, incandescent bulb,and/or excimer lamp).

In FIG. 2, an example construction of the luminaire 100 is depicted. Inthis embodiment, the luminaire 100 comprises a first optical waveguide112 a and a second optical waveguide 112 b. The first waveguide 112 ahas respective upper and lower surfaces 116, 118 while the secondwaveguide 112 b also has respective upper and lower surfaces 120, 122.The lower surface 118 of the first waveguide 112 a and the upper surface120 of the lower waveguide 112 b are disposed adjacent one another, asillustrated in FIG. 3, and aligned along a plane. The edge coupledoptical waveguides 112 of the luminaire 100 may be about 1 cm apart.Hereinthroughout, waveguides having light directed into an edge thereofmay be referred to as edge coupled and/or edge lit optical waveguideinterchangeably.

In the example embodiment of FIG. 2, the first and second waveguides 112a, 112 b are square/rectangular in shape. Therefore, the waveguides 112comprise first, second, third, and fourth edge surfaces 124 a, 124 b,124 c, 124 d. Similarly, the second waveguide 112 b comprises first,second, third, and fourth edge surfaces 124 e, 124 f, 124 g, 124 h.Extraction features 128 are disposed on one or more planar surfaces 116,118, 120, 122 of the first and second 112 a, 112 b waveguides. In thisembodiment, the first and second waveguides 112 a, 112 b may compriseother shapes (from a plan view) such as triangles, circles, ovals,asymmetric shapes, and/or other suitable shapes.

Referring still to FIGS. 2 and 3, one or more LED elements or modules130 illuminate the first and second waveguides 112 a, 112 b. The LEDs130 may be arranged as first and second pluralities of LEDs 132, 134disposed along one or more edge surfaces 124 of the first and secondwaveguides 112 a, 112 b, respectively. In FIG. 3, the luminaire 100comprises first and second pluralities of LEDs 132, 134 configured asone or more strings of LEDs 130. The first plurality of LEDs 132 isdisposed along the edge surface 124 a of the first waveguide 112 a whilethe second plurality of LEDs 134 is disposed along the edge surface 124g of the second waveguide 112 b.

Light developed by the first plurality of LEDs 132 is directed into thewaveguide body 110 of first waveguide 112 a through the edge surface 124a. Similarly, light developed by the second plurality of LEDs 134 isdirected into the second waveguide 112 b through the edge surface 124 g.In example embodiments, the pluralities of LEDs 132, 134 may extendalong more than one of the edge surfaces 124 of the first and secondwaveguides 112 a, 112 b, thereby directing light into the waveguides 112a, 112 b from more than one direction. The quantity, arrangement, andrelative locations of the LEDs 130 may be selected to introduce lightinto the first and second waveguides 112 a, 112 b in an amount and froma direction suitable for producing one or more of the above-notedappearance effects 108 and/or desired illumination effects.

Also, in example embodiments, the LEDs may be coupled to the firstand/or second waveguides 112 a, 112 b at locations other than the edges124 thereof. One or more coupling cavities may be disposed on the planarsurfaces 116, 118, 120, 122 of the first and/or second waveguides 112 a,112 b. Also, in embodiments, the LEDs 130 may be aligned with one ormore interior coupling cavities 170 (see FIG. 9B) spaced apart from theedges 124 of the waveguide(s) 112 a, 112 b. Embodiments describedhereinthroughout as edge coupled or edge lit may comprise, alternativelyor additionally, one or more interior coupling cavities and/or othersuitable LED coupling configurations for introducing light into the oneor more waveguides 112 a, 112 b.

Light is directed out and away from the first and second waveguides 112a, 112 b by the extraction features 128. Referring to FIGS. 2 and 3, inexample embodiments, extraction features 128 a of the first, upperwaveguide 112 a are disposed on the upper surface 116 thereof. Theseextraction features 128 a direct light, produced by the first pluralityof LEDs 132 and entering the first waveguide 112 a through one of theedge surfaces 124 a, 124 b, 124 c, 124 d, out of and away from the lowersurface 118 thereof. Light directed out of the lower surface 118 of theupper waveguide 112 a may enter the lower waveguide 112 b through theupper surface 120 thereof.

The upper surface 122 of the lower waveguide 112 b may also haveextraction features 128 b disposed thereon. The extraction features 128b of the lower waveguide 112 b also direct light, produced by the secondplurality of LEDs 134 and entering the second waveguide 112 b throughone of the edge surfaces 124 e, 124 f, 124 g, 124 h, out of and awayfrom the second waveguide 112 b through the lower surface 122 thereof.To produce the appearance effects 108 and illumination effectscontemplated herein, the extraction features 128 a, 128 b are disposedin different patterns 142 (see FIGS. 4-9) respectively disposed on thefirst and second waveguides 112 a, 112 b.

Referring now to FIGS. 4-6, the extraction features 128 and examples ofthe extraction feature patterns 142 are shown and described. The number,geometry, and spatial array of the extraction features 128 across awaveguide body affects the uniformity and distribution of emitted light.As shown in the example waveguide 112 in FIGS. 4-6, the discreteextraction features 128 may be formed in one or more schemes/arrays. Inexample embodiments variable extraction feature size is utilized toobtain a uniform or nearly uniform distribution of light. Specifically,the extraction features 128 may be arranged in rows and columns whereinthe features in each row extend left to right and the features in eachcolumn extend top to bottom as seen in FIGS. 2, 5, and 6. The extractionfeatures 128 closest to the LEDs 130 may be generally smaller and/ormore widely spaced apart so that along the length dimension of thewaveguide 112 the majority of light travels past such features to beextracted at subsequent parts of the waveguide 112. This results in agradual extraction of light over the length of the waveguide 112. Thecenter-to-center spacing of extraction features 128 in each row may bepreferably constant, although such spacing may be variable, if desired.The extraction features 128 contemplated herein may be formed byinjection molding, embossing, laser cutting, calendar rolling, or theextraction features may added to the waveguide 112 by a film. In furtherexample embodiments, this progression and arrangement of extractionfeatures 128 may be reversed or otherwise ordered to achieve the desiredappearance or illumination effect 108. Still further, in embodiments,the extraction features and/or extraction surfaces may be fabricated bytexturing, roughening, sanding, and/or other suitable methods ofproducing surface features for directing light out of and/or away from awaveguide 112.

The luminaire 100 may include a housing 140 (FIG. 1) comprising, amongother things, one or more of driver circuitry, the LEDs 130, controlcircuitry, sensor(s), power circuitry, circuit board(s), or othercomponents. Furthermore, luminaires described herein may be networkedwith other luminaires, to form a lighting system or lighting network,using wired connections or wireless technology and the operation thereof(on/off and/or color and/or color temperature) may be controlled asdesired, for example in coordinated or stand-alone fashion. The LEDs 130hereinthroughout may be substantially the same or modified in size,shape, color, number, and/or other characteristics to fit housing andillumination specifications of particular luminaireapplications/configurations described herein. The housing 140 furtherprovides structural support to the optical waveguides 112 a, 112 bwhereabouts said housing 140 meets one or more of the edge surfaces 124of the respective waveguides 112 a, 112 b.

Each of the LED elements or modules 130 (FIGS. 2-4 and 10) may be asingle white or other color LED chip or other bare component, or eachmay comprise multiple LEDs either mounted separately or together on asingle substrate or package to form a module including, for example, atleast one phosphor-coated LED either alone or in combination with atleast one color LED, such as a green LED, a yellow LED, a red LED, etc.In those cases where a soft white illumination with improved colorrendering is to be produced, each LED element or module 130 or aplurality of such elements or modules may include one or more blueshifted yellow LEDs and one or more red LEDs. The LEDs 130 may bedisposed in different configurations and/or layouts as desired.Different color temperatures and appearances may be produced using otherLED combinations, as is known in the art. In one embodiment, the lightsource comprises any LED, for example, an MT-G LED incorporatingTrueWhite® LED technology or as disclosed in U.S. Pat. No. 9,818,919,filed Oct. 10, 2012, entitled “LED Package with Multiple Element LightSource and Encapsulant Having Planar Surfaces” by Lowes et al., thedisclosure of which is hereby incorporated by reference herein, asdeveloped and manufactured by Cree, Inc., the assignee of the presentapplication. If desirable, a side emitting LED disclosed in U.S. Pat.No. 8,541,795, the disclosure of which is hereby incorporated byreference herein, may be utilized. In some embodiments, each of the LEDelements or modules 130 may comprise one or more LEDs disposed within acoupling cavity with an air gap being disposed between the LED elementor module 130 and a light input surface, such as the edge surfaces 124.In any of the embodiments disclosed herein each of the LED element(s) ormodule(s) 130 preferably have a lambertian or near-lambertian lightdistribution, although each may have a directional emission distribution(e.g., a side emitting distribution), as necessary or desirable. Moregenerally, any lambertian, symmetric, wide angle, preferential-sided, orasymmetric beam pattern LED element(s) or module(s) may be used as thelight source. Still further, any of the LED arrangements and opticalelements disclosed in U.S. Pat. No. 9,869,432, filed Dec. 9, 2013,entitled “Luminaires Using Waveguide Bodies and Optical Elements” byKeller et al., which is hereby incorporated by reference herein, may beused.

The waveguides 112 contemplated herein may be tapered depending onapplication. Tapering a waveguide body causes light to reflectinternally along the length of the waveguide body while increasing theangle of incidence. Eventually, this light strikes one side at an anglethat allows the light to escape. The opposite example, i.e., a graduallythickening waveguide body over the length thereof, causes light tocollimate along the length with fewer and fewer interactions with thewaveguide body surfaces. These interactions can be used to extract andcontrol light within the waveguide. When combined with dedicatedextraction features, tapering allows one to change the incident angulardistribution across an array of features. This, in turn, controls howmuch, and in what direction light is extracted. Thus, a selectcombination of tapered surfaces and extraction features may achieve adesired illumination and appearance. Any combination of these featuresmay be employed by the waveguides 112 of the presently describedluminaire/lighting system 100, 104.

According to one aspect, a waveguide directs light into at least one, upto an infinite number, of beams or ray groups, wherein the rays of eachgroup travel through the waveguide within a range of angles relative toone another. Each range may be narrow or broad within the TIR limits ofthe waveguide material. According to another aspect, a waveguidearranges light into a plurality of groups that bounce at least onceinside the waveguide by TIR off one or more surfaces of the waveguide.Each group comprises a plurality of light rays that travel at anglesthat are disposed within a narrow or broad range of angles relative toone another. In any embodiment, the range may be so narrow that thelight rays of ray group may be considered to be fully collimated, ornearly so, or the range may be so broad that the light rays of a raygroup may be considered to be anti-collimated, or nearly so. Controllingthe ray angles in this manner can lead to increased light control,reduced waveguide size and weight, and reduced luminaire costs.

Referring now to FIGS. 7-9, optical waveguides 112 that may comprise thefirst and second waveguides 112 a, 112 b of the luminaire 100 aredepicted such that the extraction features 128 disposed thereon form oneor more of the extraction feature patterns 142. An extraction featurepattern 142 a shown in FIG. 7 is concentrated at an interior portion 144of the waveguide 112 while a peripheral portion 146 does not haveextraction features disposed thereon. Accordingly, light introducedthrough one or more of the edge surfaces 124 traverses the peripheralportion 146 such that substantially all of said light is totallyinternally reflected. Once this edge coupled TIR light reaches theinterior portion 144 it is directed out of and/or away from thewaveguide by the extraction features 128 of the interior-concentratedextraction feature pattern 142 a. Therefore, the waveguide 112 of FIG. 7primarily emits light from the interior portion 144 thereof. FIG. 10 isa photograph depicting the waveguide 112, having the extraction featurepattern 142 a of FIG. 7, with blue and/or violet light (such as lightcomprising a color temperature of about or greater than 10,000K andpreferably about 16,000K) being introduced into the edge surface 124 ofsaid waveguide 112 by LEDs. The illuminated waveguide 112 of thisphotograph does not emit light from the peripheral portion 146 but doesemit light from the interior portion 144 whereon the extraction features128 are disposed.

FIG. 8 illustrates an embodiment of the optical waveguide(s) 112comprising another extraction feature pattern 142 b. In this extractionfeature pattern 142 b, the extraction features 128 are concentrated inthe peripheral portion 146 of the waveguide 112 while the interiorportion 144 of the waveguide 112 does not have extraction featuresdisposed thereon. Therefore, substantially all of the light introducedinto the example waveguide 112 of FIG. 8 is directed out of and awayfrom the waveguide by the extraction features 128 in the peripheralportion 146. Edge coupled light that is not extracted before reachingthe interior portion 144 may be TIR while traversing the interiorportion 144 and subsequently extracted by the extraction features 128 onanother side of the waveguide 112 upon reaching same. FIG. 11 is aphotograph depicting the waveguide 112, having the extraction featurespattern 142 b of FIG. 8, with yellow light (such as light comprising acolor temperature of about 3000 k) introduced into the edge surface 124of said waveguide 112 by the LEDs 130. The illuminated waveguide 112 ofthis photograph emits light from the peripheral portion 146, whereon theextraction features 128 are disposed, but does not emit light from theinterior portion 144.

The example embodiment of the optical waveguide 112 shown in FIG. 9comprises another embodiment of an extraction feature pattern 142 ccomprising arrangement of the extraction features 128 in the peripheralportion 146 as well as first and second transition portions 148 a-148 d,150 a-150 d. In the extraction feature pattern 142 c, the peripheralportion 146 is separated into four peripheral quadrants 146 a, 146 b,146 c, 146 d by boundary lines 152 a-152 d. The boundary lines 152extend from each corner of the generally square/rectangular waveguide112 to define the peripheral quadrants 146 as generally trapezoidal.Associated with and disposed adjacent to each of the peripheralquadrants 146 a-146 d are the respective first and second transitionportions 148 a-148 d, 150 a-150 d. The first, intermediate transitionportions 148 are disposed between each of the peripheral quadrants 146a-146 d and the second, interior transition portions 150 a-150 d. Inexample embodiments, the density of the extraction features 128 (ordegree of roughening/texturing) may decrease gradually from theperipheral quadrants 146 a-146 d to the intermediate transition portions148 a-148 d to the interior transition portions 150 a-150 d. In thisembodiment, a relatively larger proportion of light is extracted by thedenser extraction feature arrangement of the peripheral quadrants 146a-146 d. An intermediate proportion of light, that is relatively lessthan that extracted by the peripheral quadrants 146 a-146 d, isextracted by the intermediate transition portions 148 a-148 d. A stillrelatively lesser proportion of light, relative the intermediatetransition portions 148 a-148 d, is extracted by the interior transitionportions 150 a-150 d. The interior portion 144 of the waveguide 112 ofFIG. 9 does not have extraction features disposed thereon and totallyinternally reflects light that has been coupled into the waveguide.

In an example arrangement of the luminaire 100, the first waveguide 112a comprises the extraction feature pattern 142 a (FIG. 7) havinginterior extraction features and the second waveguide 112 b comprisesone of the extraction feature patterns 142 b, 142 c with peripheralextraction features (FIGS. 8 and 9). Example embodiments of theluminaire 100 are depicted in the photographs of FIGS. 12-14. The e ofthe luminaire 100 a shown in FIG. 12 comprises first and secondwaveguides 112 a, 112 b having respective extraction feature patterns142 a and 142 b. In this embodiment, blue and/or violet light (such aslight comprising a color temperature of about or greater than 10,000Kand preferably about 16,000K) is edge coupled into the first waveguide112 a while yellow light (such as light comprising a color temperatureof about 3000 k) is edge coupled into the second waveguide 112 b. Lightis emitted into an illuminated space, such as a room, through the lowersurface 122 of the second waveguide 112 b.

The appearance effect 108 produced by this example embodiment is ayellow perimeter, wherefrom light is emitted according to the extractionfeature pattern 142 b of the second waveguide 112 b, disposed about ablue/violet interior, wherefrom light is extracted by the extractionfeature pattern 142 a of the first waveguide 112 a. The blue/violetlight emitted from the lower surface 116 (FIG. 3) of the first waveguide112 a enters the upper surface 120 (FIG. 3) of the second waveguide 112b, passes therethrough relatively unobstructed, and is emitted from thelower surface 122 of the second waveguide 112 b. The photographedembodiment produces the appearance effect 108 of a skylight such that anoccupant of the illuminated space perceives a desirable yellow lightemitted from a blue sky illusion/appearance.

In general, the luminaire(s) 100 is configured to emit light and providethe appearance of the sky to a viewer. For the concepts contemplated bythe present disclosure, the luminaire(s) 100 are configured to emulatesunlight coming through a skylight directly at a particular angle orbeing reflected off of a sidewall. Accordingly, the luminaire(s) 100 maybe arranged to provide generally non-directional light associated withthe sky as well as emulate the direct sunlight or a reflection thereoffrom the sun. Depending on the time of day or night, the intensity,color temperature, and/or color of light emitted from the luminaire(s)100 may vary in an effort to emulate the light provided by aconventional skylight at different times of the day or night and anytransitions therebetween.

Referring back to FIG. 9B, an example embodiment of a waveguide 112 d isdepicted. The waveguide 112 d comprises both the interior and peripheralextraction feature patterns 142 a, 142 b. The LEDs 130 may be coupled tothe edge 124 as well as disposed in the interior coupling cavity 170.Light from the LED(s) 130 disposed in the interior coupling cavity 170is directed out of the waveguide 112 d by the interior extractionfeature pattern 142 a. Light from the LED(s) 130 disposed along the edge124 of the waveguide 112 d is directed out of the waveguide 112 d by theperipheral extraction feature pattern 142 b. The LED(s) 130 at theinterior coupling cavity 170 and the waveguide edges 124 may couple intothe waveguide 112 d light of the same or different spectrums, colors,correlated color temperatures (CCT), and/or other light qualities.Therefore, the light extracted by the interior and peripheral portions144, 146 may have different spectrum qualities and/or differentdirectional components. Any of the extraction feature patterns 142described herein may be combined on a single waveguide, such as is shownin FIG. 9B. The luminaire(s) 100 may comprise a single waveguide thatemits light similar and/or in accordance with embodiments describedherein as comprising two waveguides. Further, in FIG. 9B the extractionfeatures 128 in the respective interior and exterior portions 144, 146may be the same or different. One or more specular barriers, grooves,and/or other characteristics of the waveguide body 110 may separateextraction feature patterns 142 when disposed on the same waveguide 112.Embodiments described hereinthroughout may extract light comprising afirst spectrum from one portion of a waveguide body and light comprisinga second spectrum from another portion of the waveguide body. Light fromlight sources comprising different spectrums (or other characteristics)may or may not be mixed within the waveguide body 100 before extractionto achieve the desired appearance effect 108.

In the embodiments of the luminaire 100 shown in FIGS. 13 and 14, thefirst waveguide comprises the extraction feature pattern 142 a (FIG. 7)having interior extraction features, and the second waveguide 112 bcomprises the extraction feature pattern 142 c (FIG. 9A) havingperipheral quadrants 146 a-146 d, boundary lines 152 a-152 d, and firstand second transition portions 148 a-148 d, 150 a-150 d. With similarityto FIG. 12, the appearance effect 108 of a yellow perimeter disposedabout a blue/violet interior is developed. In the photographedembodiment of FIGS. 13 and 14, the first and second transition portions148 a-148 d, 150 a-150 d, which comprise relatively fewer extractionfeatures 128 as compared with the peripheral quadrants 146 a-146 d,operate to extract some yellow light while also permitting someblue/violet light, emitted from the first waveguide 112 a, to passtherethrough. Accordingly, the transition surfaces 148 a-148 d, 150a-150 d, in conjunction with the boundary lines 152 a-152 d develop aperception of depth when viewed by a user occupying the illuminatedspace. This may further complement the appearance effect 108 of askylight. As desired, the luminaire 100 produces the illusion of depthin a relatively thin, flat luminaire construction utilizing twowaveguides configured and aligned one atop/behind the other.

In example embodiments, a material may be disposed between the first andsecond waveguides 112 a, 112 b. The material may be specular orotherwise suitably reflective and/or absorptive. The material betweenthe waveguides 112 a, 112 b may prevent light extracted out of the firstwaveguide 112 a from portions of the waveguide 112 a comprising anextraction pattern that overlaps with portions of the second waveguidethat also comprise an extraction pattern. For example, the extractionfeature pattern 142 a may overlap with the extraction feature pattern142 b. In this example, the material disposed between the first andsecond waveguides 112 a, 112 b may prevent undesirable light/colormixing at the overlapping edges of the first and second extractionfeature patterns 142 a, 142 b.

Referring now to FIGS. 15-23, example embodiments of the luminaire 100comprise patterns on the waveguide surface that utilize geometricaland/or linear shapes to develop the perception and/or illusion of avanishing point. The appearance effects 108 shown in the photographs ofthe luminaire 100 in FIGS. 17-19, 21, and 22 produce the illusion ofdepth on a substantially flat, light emitting surface of the waveguide112. FIGS. 15, 16, 20, and 23 depict mask elements 154 that may be usedto produce extraction feature patterns 142 on the waveguides 112. Themask element 154 a of FIGS. 15 and 16 produces the extraction featurepattern 142 d used to develop the appearance effect 108 of FIGS. 17-19.The mask element 154 b of FIG. 20 may be used to product the extractionfeature pattern 142 e that develops the appearance effect 108 of FIGS.21 and 22. The mask element 154 c of FIG. 23 may produce yet anotherextraction feature pattern that results in the illusion of depth whenviewed by an occupant of a space illuminated by the luminaire 100.

In example embodiments, the extraction feature patterns 142 may includeextraction features on both sides of the waveguide 112 and/or theextraction features 128 disposed at various portions of the waveguide112 may direct light out of the waveguide in different directions. Inthe example embodiment of the luminaire 100 shown in FIGS. 17-19, onlyone waveguide 112 c is used to produce the illusion of depth. The maskelement 154 a may be used in fabricating the extraction features 128disposed on upper and/or lower surfaces 156, 158 of the waveguide 112 c.The waveguide 112 c of this embodiment may have on the upper surface 156thereof upper surface extraction features 128 c that extract/directproportionally more light out of the lower surface 158 of the waveguide112 c thereby developing bright portions 160 wherefrom relatively morelight emanates. The lower surface 158 of this waveguide 112 c may havecomplementary lower surface extraction features 128 d that extractrelatively less light out of the lower surface 158 of the waveguide 112c as compared to the upper surface extraction features 128 c therebydeveloping dimmer portions 162. The complementary arrangement of thebright portions 160 and the dimmer portions 162 develops the appearanceeffect 108 of a vanishing point 164 disposed proximal a center of thewaveguide 112 c shown in FIGS. 17-19. In example embodiments, the upperand lower extraction features 128 c, 128 d may be arranged such that thevanishing point 164 is disposed elsewhere on the waveguide 112 c whenviewed by the occupant of an illuminated space. For example, thevanishing point 164 may be nearer a corner of the waveguide 112 c. Asshown in the photographs of FIGS. 18 and 19, the appearance effect 108produced by this embodiment allows the bright and dimmer portions 160,162 to complement and interact with one another in desirable ways whenviewed from different angles.

Also in example embodiments, such as are shown in the photographs ofFIGS. 21 and 22, the extraction feature patterns 142 disposed on thefirst and second waveguides 112 a, 112 b may be arranged to developbright portions 166 and dimmer portions 168 that are further enhanced bycolor selection of the edge coupled LEDs 130 respectively associatedwith the first and second waveguides 112 a, 112 c. For example, thelower waveguide 112 b depicted in FIG. 21 and having an extractionfeature pattern 142 e fabricated with the mask element 154 b may beoperatively paired with the upper waveguide 112 c depicted in FIG. 9. Insuch an embodiment, the violet light emitted by the upper waveguide 112a may further enhance the illusion of depth and appearance of avanishing point 164 produced by the bright and dimmer portions 166, 168of the second waveguide 112 b, as shown in FIG. 22.

In example embodiments, a plurality of the luminaires 100 such as thoseshown in FIGS. 17-19, 21, and 22 with vanishing points 164 at the sameor different positions relative the viewer/occupant may line a ceilingor hallway to develop desirable artistic, aesthetic, and/orarchitectural concepts. The colors and extraction feature patternsdisposed on each waveguide of such a configuration of plural luminairesmay be customized/selected to highlight or enhance some portion of theilluminated space, interior and/or exterior architecture, and/orotherwise produce desirable overall visual effects or patterns. Theluminaire(s) 100 may operate as a primary light source or as adecorative/architectural element complementary to other existingfunctional and/or decorative luminaries.

As noted, embodiments of the luminaire 100 may be configured the same ordifferently with respect to the lighting capabilities andcharacteristics thereof. In order to meet the specifications ofparticular applications, the luminaire(s) 100 may be designed to operateat different intensity levels, colors, color temperatures, lightdistributions, illumination patterns, and/or other lightingcharacteristics. Further, more than one of the luminaire(s) 100 may bedesigned and/or controlled such that each panel provides light withdifferent characteristics, yet the light from the overall lightingsystem 104 combines to provide light with characteristics that may bedifferent from the individual luminaire(s) 100 of the system 104.

In example embodiments, the luminaire(s) 100 may emulate the directionalnature of sunlight passing through a conventional skylight, such asduring different times of day with corresponding sun positions. Theluminaire(s) 100 may be arranged to emulate the appearance of the skyand the non-directional nature of sunlight passing through aconventional skylight. The luminaire(s) 100 may be further configured toemulate the appearance of light passing through or being reflected fromwindow and side walls of a conventional skylight.

Also in embodiments contemplated by this disclosure, the light exitingone or more portions of the luminaire(s) 100 may be relatively shiftedtoward blue in the light spectrum to emulate the appearance of a bluesky. The light exiting one or more other portions of the luminaire(s)100 may be relatively shifted toward red in the light spectrum to betteremulate the appearance of sunlight. The luminaire(s) 100 may beconfigured to vary the color, illumination pattern, and/or intensity ofemitted light during operation emulate, track, and/or react to changingconditions of outside environments throughout the day and night. Forexample, it may be desirable for the luminaire(s) 100 to emulate theappearance effect 108 of blue sky and sunlight during night time and/orduring weather events, e.g., cloudiness or fog. Also, embodiments mayemulate a conventional skylight during predominately daylight hoursbetween, but not necessarily including, the sunrise and sunset where thesky may appear less blue and more reddish orange. To expand thefunctionality of the luminaire(s) 100 to better emulate the appearanceof a conventional skylight outside of daylight hours, operation inexpanded color spaces and/or with more or less color mixing may bedesirable. For example, the colors emitted by the luminaire(s) 100 maybe shifted or expanded to address the deeper blues associated with dusk,dawn, and nighttime as well as the more reddish orange and red huesassociated with sunrise and sunset.

In example embodiments, the LEDs 130 are coupled to one or more portionsof the optical waveguide(s) 112. As mentioned hereinabove, the LEDs 130may be disposed as strings or groups. Each string or group of LEDs 130may comprise one color or more than one color of LEDs. A two-color LEDstring may comprise a plurality of LEDs of a first color and a pluralityof LEDs of a second color. Therefore, the color and number of the LEDs130 may be varied to introduce an overall color into the waveguide body110 that is a combination of the color produced by the individual LEDs130 of an LED string or group. The overall spectrum of light introducedinto the waveguide body 110 may be controlled by the combination of LEDsselected and/or the extent to which the different LEDs are energized.

For example, the LEDs 130 introducing light into a portion of thewaveguide body 110 may be bluish LEDs that emit bluish light comprisinga 475 nm dominant wavelength and an overall bluish spectrum illustratedin FIG. 24, which is a graph of output intensity versus wavelength.Further, the LEDs 130 may be white LEDs that emit white light comprisinga color temperature of approximately 5000K (+/−0.5, 1, 2, or 5%) and acolor rendering index (CRI) of at least 85 or 90 (i.e. CRI 85, CRI 90).Example white LEDs may emit an overall spectrum that is illustrated inFIG. 25, which is a graph of output intensity versus wavelength.

In example embodiments, the overall spectrum of the emitted light fromthe luminaire(s) 100 may be increased by using three or more LEDscomprising different colors. Using three or more colors of the LEDs 130may be desirable for creating complex light that increases the accuracywith which the luminaire(s) 100 emulate sunlight. An example of a threecolor-LED combination may comprise deeper bluish LEDs, greenish LEDs,and white LEDs. Example bluish LEDs may comprise a 418 nm dominantwavelength and an overall spectrum (primary spectrum of 505 nm-530 nm)that is illustrated in FIG. 26, which is a graph of output intensityversus wavelength. Example greenish LEDs may comprise a 458 nm dominantwavelength and an overall spectrum (primary spectrum of 450 nm-465 nm)that is illustrated in FIG. 27, which is a graph of output intensityversus wavelength. Example white LEDs may comprise a color temperatureof approximately 5000K (+/−0.5, 1, 2, or 5%) and a color rendering index(CRI) of at least 85 or 90 (i.e. CRI 85, CRI 90). Also, example whiteLEDs may comprise an overall spectrum that is illustrated in FIG. 28,which is a graph of output intensity versus wavelength. While certaincolors of LEDs are used in the described embodiments, LEDs of variouscolors and combinations thereof are considered within the scope of thedisclosure. A three color LED combination of the above-mentioned exampleLEDs may supply light to the first waveguide 112 a and/or the interiorportion 144 of a single waveguide embodiment of the luminaire(s) 100.

As noted hereinabove, the respective portions 144, 146 and/or therespective waveguides 112 a, 112 b of the luminaire(s) 100 may beindividually controlled such that light introduced therein and emittedthereby may be of different colors or spectrums at any selected time.The particular spectrums and/or colors for particular portions and/orwaveguides may be permanently fixed or dynamically controlled such thatthe appearance effect(s) 108 produced by the emitted light may changebased on user input, a predefined program, and/or as a function of anynumber or combination of control inputs/variables. The control inputsmay include date, day, time of day, sensor outputs (such as indoorand/or outdoor temperature sensors, light sensors, motion sensors,humidity sensors, rain sensors, and/or other suitable sensors),architectural/structural qualities of the building in which theluminaire(s) 100 is disposed, and/or other suitable control inputs.

The luminaire(s) 100 may be further controlled such that the compositelighting output produced thereby supplies a certain color, colortemperature, CRI, and/or otherwise suitable light while achieving otherlighting goals, such as emulating a conventional skylight, developing adepth effect, creating a vanishing point, enhancing room aesthetics,highlight architectural features, and/or other suitable lighting goals.

A networked plurality of the luminaire(s) 100 may be controlledcollectively by a remote source, by a master fixture, or in adistributed fashion to operate in concert to present a static or dynamicscene. Each of the luminaire(s) 100 may have different or the same lightoutput depending on the desired scene lighting. In one scenario, each ofthe luminaire(s) 100 may provide the same light output for a scene, suchthat each of the luminaire(s) 100 comprises the same appearance effect108 for a uniform scene. In another scenario, two or more of theluminaire(s) 100 comprise different light output configurations, whereineach of the luminaire(s) 100 represents a portion of an overall scene.The luminaire(s) 100 may also be controlled to provide virtually anytype of mood, theme, holiday, and/or like lighting as well wherein thecolor, color temperature, brightness, and spectral content of the lightemitted from the luminaire(s) 100 is fully customizable throughselection of the light sources and the control thereof. The luminaire(s)100 may be controlled or configured to operate in different modes atdifferent times or in response to sensor input or outside control input.

For example, the luminaire(s) 100 may function to emulate a conventionalskylight with a changing scene that tracks outside conditions duringbusiness hours and transitions to decorative accent lighting mode duringnon-business hours. Alternatively, the luminaire(s) 100 may transitionto a mode that enhances alertness or provides some other type ofcircadian stimuli after normal business hours. Again, such control maybe provided by a programming of the luminaire(s) 100, remote control,and/or control based on various inputs from other sensors and controls.The independent control and the potential for different capabilities andconfigurations of the luminaire(s) 100 provides flexibility andcustomization for a luminaire, waveguide, and/or waveguide assemblyemitting different spectrums of light from discrete portions thereof.The luminaire(s) 100 described herein may include the control,functionality, and/or LED/color point combinations disclosed incopending U.S. Patent Application Publication Nos. 2018-0252374A1 and2018-0259140A1, both entitled “Skylight Fixture,” and filedcontemporaneously with the present application, the disclosures of whichare hereby incorporated by reference herein.

In an example embodiment, the light source(s)/LEDs 130 may comprisethree (or more) LED types such that the light emitted by theluminaire(s) 100 may be precisely controlled a in two-dimensional colorspace (e.g. to stay on the black body locus at any achievable CCTvalue). In other embodiments, the color gamut of the selected LED typesmay have a range such that the achievable CCT/color range iscorrespondingly larger. In particular, the choice of warm white LEDs inthe luminaire(s) 100, including but not limited to BSY+BSY+RDOcombinations such as are found in Cree True White fixtures (“BSY” is ablue-shifted yellow LED; and “RDO” is a red-orange LED corresponding tolight emitted with a dominant wavelength between 600 nm and 630 nm). Forexample, it may be desirable for the luminaire(s) 100 to produce lightcomprising a color similar to natural light around sunset, which mayhave a low CCT (<2700K).

Any of the embodiments disclosed herein may include a power circuit thatmay further be used with light control circuitry that controls colortemperature of any of the embodiments disclosed herein in accordancewith viewer/occupant input such as disclosed in U.S. Patent ApplicationPublication No. 2015-0351187A1, entitled “Lighting Fixture ProvidingVariable CCT” by Pope et al., the disclosure which is herebyincorporated by reference herein.

Further, any of the embodiments disclosed herein may include one or morecommunication components forming a part of the light control circuitry,such as an RF antenna that senses RF energy. The communicationcomponents may be included, for example, to allow the luminaire tocommunicate with other luminaires and/or with an external wirelesscontroller, such as disclosed in U.S. Pat. No. 8,975,827, entitled“Lighting Fixture for Distributed Control” or U.S. ProvisionalApplication No. 61/932,058, filed Jan. 27, 2014, entitled “EnhancedNetwork Lighting” both owned by the assignee of the present applicationand the disclosures of which are hereby incorporated by referenceherein. More generally, the control circuitry includes at least one of anetwork component, an RF component, a control component, and a sensor.The sensor may provide an indication of ambient lighting levels theretoand/or occupancy within the illuminated area. Such sensor may beintegrated into the light control circuitry and may cause the luminaireto adjust output lighting levels as a function of ambient light levelsand/or detected motion.

INDUSTRIAL APPLICABILITY

In summary, the luminaire contemplated hereinabove may be relativelythin and conducive to surface mounting and/or mounting within ceilingsand/or walls with very thin plenums, e.g., 4-6 inches, by using one ormore flat, planar waveguides to deliver light. Skylights comprisingwaveguides may improve the ease of manufacture, power efficiency, anddecrease material and manufacturing costs associated with producingother skylights and/or skylight replacement-type fixtures. A dualwaveguide luminaire comprises one waveguide that is edge coupled withLEDs to produce a predominantly blue light emulating a blue sky and asecond separate waveguide edge coupled with LEDs to create apredominantly white light emulating sunlight derived from a blue sky.The first and second light emitting surfaces do not substantiallyoverlap in physical alignment/orientation so that light from thedifferent waveguides does not color mix, as such mixing may produce anundesirable third color perception. To accomplish this, the firstwaveguide may comprise extraction features that are populated proximal acentral portion of the waveguide, and the second waveguide may compriseextraction features that are disposed about a peripheral region of thesecond waveguide. When the first waveguide is illuminated with bluelight the center/interior glows blue. Likewise, when the secondwaveguide is illuminated with white light the periphery thereof glowswhite. This arrangement creates the illusion of a skylight housed withina thin and flat construction. The light sources do not need to be blueand/or white, but instead may be any other color, such as a differentCCT white light, to differently develop the illusion of depth. Further,the light sources may produce light of different brightness/lumenlevels.

When one uses a relatively small light source which emits into a broad(e.g., Lambertian) angular distribution (common for LED-based lightsources), the conservation of etendue, as generally understood in theart, requires an optical system having a large emission area to achievea narrow (collimated) angular light distribution. In the case ofparabolic reflectors, a large optic is thus generally required toachieve high levels of collimation. In order to achieve a large emissionarea in a more compact design, the prior art has relied on the use ofFresnel lenses, which utilize refractive optical surfaces to direct andcollimate the light. Fresnel lenses, however, are generally planar innature, and are therefore not well suited to re-directing high-anglelight emitted by the source, leading to a loss in optical efficiency. Incontrast, in the present disclosure, light is coupled into the optic,where primarily TIR is used for re-direction and collimation. Thiscoupling allows the full range of angular emission from the source,including high-angle light, to be re-directed and collimated, resultingin higher optical efficiency in a more compact form factor.

In at least some of the present embodiments, the distribution anddirection of light within the waveguide is better known, and hence,light is controlled and extracted in a more controlled fashion. Instandard optical waveguides, light bounces back and forth through thewaveguide. In the present embodiments, light is extracted as much aspossible over one pass through the waveguide to minimize losses.

In some embodiments, one may wish to control the light rays such that atleast some of the rays are collimated, but in the same or otherembodiments, one may also wish to control other or all of the light raysto increase the angular dispersion thereof so that such light is notcollimated. In some embodiments, one might wish to collimate to narrowranges, while in other cases, one might wish to undertake the opposite.

As in the present embodiments, a waveguide may include variouscombinations of mixing features, extraction features, and redirectionfeatures necessary to produce a desired light distribution. A lightingsystem may be designed without constraint due to color mixingrequirements, the need for uniformity of color and brightness, and otherlimits that might otherwise result from the use of a specific lightsource. Further, the light transport aspect of a waveguide allows forthe use of various form factors, sizes, materials, and other designchoices. The design options for a lighting system utilizing a waveguideas described herein are not limited to any specific application and/or aspecific light source.

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

The word exemplary is used to mean serving as an example orillustration. To the extent that the term include, have, or the like isused, such term is intended to be inclusive in a manner similar to theterm comprise as comprise is interpreted when employed as a transitionalword in a claim. Relational terms such as first and second and the likemay be used to distinguish one entity or action from another withoutnecessarily requiring or implying any actual such relationship or orderbetween such entities or actions.

Phrases such as an aspect, the aspect, another aspect, some aspects, oneor more aspects, an implementation, the implementation, anotherimplementation, some implementations, one or more implementations, anembodiment, the embodiment, another embodiment, some embodiments, one ormore embodiments, a configuration, the configuration, anotherconfiguration, some configurations, one or more configurations, thesubject technology, the disclosure, the present disclosure, othervariations thereof and alike are for convenience and do not imply that adisclosure relating to such phrase(s) is essential to the subjecttechnology or that such disclosure applies to all configurations of thesubject technology. A disclosure relating to such phrase(s) may apply toall configurations, or one or more configurations. A disclosure relatingto such phrase(s) may provide one or more examples. A phrase such as anaspect or some aspects may refer to one or more aspects and vice versa,and this applies similarly to other foregoing phrases.

The disclosed systems and methods are well adapted to attain the endsand advantages mentioned as well as those that are inherent therein. Theparticular implementations disclosed above are illustrative only, as theteachings of the present disclosure may be modified and practiced indifferent but equivalent manners apparent to those skilled in the arthaving the benefit of the teachings herein. It is therefore evident thatthe particular illustrative implementations disclosed above may bealtered, combined, or modified and all such variations are consideredwithin the scope of the present disclosure. The systems and methodsillustratively disclosed herein may suitably be practiced in the absenceof any element that is not specifically disclosed herein and/or anyoptional element disclosed herein. All numbers and ranges disclosedabove may vary by some amount. Whenever a numerical range with a lowerlimit and an upper limit is disclosed, any number and any included rangefalling within the range are specifically disclosed. In particular,every range of values (of the form, “from about a to about b,” or,equivalently, “from approximately a to b,” or, equivalently, “fromapproximately a-b”) disclosed herein is to be understood to set forthevery number and range encompassed within the broader range of values.Also, the terms in the claims have their plain, ordinary meaning unlessotherwise explicitly and clearly defined by the patentee. Moreover, theindefinite articles “a” or “an,” as used in the claims, are definedherein to mean one or more than one of the element that it introduces.If there is any conflict in the usages of a word or term in thisspecification and one or more patent or other documents that may beincorporated herein by reference, the definitions that are consistentwith this specification should be adopted.

A phrase “at least one of” preceding a series of items, with the terms“and” or “or” to separate any of the items, modifies the list as awhole, rather than each member of the list. The phrase “at least one of”does not require selection of at least one item; rather, the phraseallows a meaning that includes at least one of any one of the items,and/or at least one of any combination of the items, and/or at least oneof each of the items. By way of example, each of the phrases “at leastone of A, B, and C” or “at least one of A, B, or C” refers to only A,only B, or only C; any combination of A, B, and C; and/or at least oneof each of A, B, and C.

In one aspect, a term coupled or the like may refer to being directlycoupled. In another aspect, a term coupled or the like may refer tobeing indirectly coupled. Terms such as top, bottom, front, rear, side,horizontal, vertical, and the like refer to an arbitrary frame ofreference, rather than to the ordinary gravitational frame of reference.Thus, such a term may extend upwardly, downwardly, diagonally, orhorizontally in a gravitational frame of reference.

The use of the terms “a” and “an” and “the” and similar references inthe context of the present disclosure (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. Recitation of ranges of values herein are merely intended toserve as a shorthand method of referring individually to each separatevalue falling within the range, unless otherwise indicated herein, andeach separate value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context. The use of any and allexamples, or exemplary language (e.g., “such as”) provided herein, isintended merely to better illuminate the disclosure and does not pose alimitation on the scope of the disclosure. No language in thespecification should be construed as indicating any non-claimed elementas essential to the practice of the disclosure.

Numerous modifications to the present disclosure will be apparent tothose skilled in the art in view of the foregoing description. It shouldbe understood that the illustrated embodiments are exemplary only, andshould not be taken as limiting the scope of the disclosure.

What is claimed is:
 1. A lighting system comprising: first and secondwaveguides arranged parallel to a plane, disposed adjacent to oneanother, and defining first and second substantially planarlight-emitting surfaces, respectively; and a plurality of light emittingdiodes including at least one first light emitting diode configured forcoupling light into the first waveguide, and at least one second lightemitting diode configured for coupling light into the second waveguide;wherein light emitted from the first waveguide traverses the secondwaveguide such that the light appears to have a source depth greaterthan a location of the first waveguide; wherein the at least one firstlight emitting diode and first waveguide are configured to output lightof a first color or first correlated color temperature; wherein the atleast one second light emitting diode and second waveguide areconfigured to output light of a second color or second correlated colortemperature that differs from the first color or first correlated colortemperature; and wherein the lighting system is configured to be mountedwithin or against a ceiling surface, and is configured to produceemissions providing an appearance of a skylight without transmission ofexterior light through any portion of the lighting system.
 2. Thelighting system of claim 1, wherein the at least one first lightemitting diode and first waveguide are configured to output blue orblue/violet light, and the at least one second light emitting diode andsecond waveguide are configured to output yellow light.
 3. The lightingsystem of claim 1, wherein: the at least one first light emitting diodeand first waveguide are configured to output light having a greaterfraction of blue light than output by the at least one second lightemitting diode and second waveguide; and the at least one second lightemitting diode and second waveguide are configured to output lighthaving a greater fraction of red light than output by the at least onefirst light emitting diode and first waveguide.
 4. The lighting systemof claim 1, wherein: the first waveguide comprises an interior couplingcavity spaced apart from edges of the first waveguide and configured toreceive emissions from the at least one first light emitting diode; andthe second waveguide comprises an edge coupling cavity arranged at anedge of a body of the second waveguide and configured to receiveemissions from the at least one second light emitting diode.
 5. Thelighting system of claim 1, wherein: the first waveguide comprises afirst extraction feature pattern arranged at a central portion of thefirst waveguide; and the second waveguide comprises a second extractionfeature pattern arranged at a peripheral portion of the secondwaveguide.
 6. The lighting system of claim 1, comprising at least one ofthe following features (i) or (ii): (i) at least some features of thefirst extraction feature pattern are arranged along an inner face and anouter face of the first waveguide; (ii) at least some features of thesecond extraction feature pattern are arranged along an inner face andan outer face of the second waveguide.
 7. The lighting system of claim1, further comprising a patterned material arranged between the firstwaveguide and the second waveguide, wherein the patterned material isconfigured to affect interaction between light emissions of the firstwaveguide and light emissions of the second waveguide.
 8. The lightingsystem of claim 1, further comprising a reflector, wherein the firstwaveguide is positioned between the reflector and the second waveguide.9. The lighting system of claim 1, wherein: the at least one first LEDcomprises a plurality of first LEDs of different colors and/or colortemperatures to permit adjustment of color and/or color temperature ofthe plurality of first LEDs; and the at least one second LED comprises aplurality of second LEDs of different colors and/or color temperaturesto permit adjustment of color and/or color temperature of the pluralityof second LEDs.
 10. A lighting system comprising: first and secondwaveguides defining first and second substantially planar light-emittingsurfaces, respectively; and a plurality of light emitting diodesincluding at least one first light emitting diode configured forcoupling light into the first waveguide, and at least one second lightemitting diode configured for coupling light into the second waveguide;wherein the at least one first light emitting diode and first waveguideare configured to output light of a first color or first correlatedcolor temperature, and predominantly in a first direction; wherein theat least one second light emitting diode and second waveguide areconfigured to output light of a second color or second correlated colortemperature that differs from the first color or first correlated colortemperature, and predominantly in a second direction that differs fromthe first direction; and wherein the lighting system is configured to bemounted within or against a ceiling surface, and is configured toproduce emissions providing an appearance of a skylight withouttransmission of exterior light through any portion of the lightingsystem.
 11. The lighting system of claim 10, wherein the at least onefirst light emitting diode and first waveguide are configured to outputblue or blue/violet light, and the at least one second light emittingdiode and second waveguide are configured to output yellow light. 12.The lighting system of claim 10, wherein: the at least one first lightemitting diode and first waveguide are configured to output light havinga greater fraction of blue light than output by the at least one secondlight emitting diode and second waveguide; and the at least one secondlight emitting diode and second waveguide are configured to output lighthaving a greater fraction of red light than output by the at least onefirst light emitting diode and first waveguide.
 13. The lighting systemof claim 10, being configured to adjust directionality of aggregateemissions of the lighting system to emulate a direction nature ofsunlight passing through at least one of the first or second waveguidesat different times of day.
 14. The lighting system of claim 10, whereinthe first and second waveguides are arranged parallel to a single planeand are disposed adjacent to one another.
 15. The lighting system ofclaim 14, wherein light emitted from the first waveguide traverses thesecond waveguide such that the light appears to have a source depthgreater than a location of the first waveguide.
 16. The lighting systemof claim 15, wherein: the first waveguide comprises a first extractionfeature pattern arranged at a central portion of the first waveguide;and the second waveguide comprises a second extraction feature patternarranged at a peripheral portion of the second waveguide.
 17. Thelighting system of claim 14, wherein: the first waveguide comprises aninterior coupling cavity spaced apart from edges of the first waveguideand configured to receive emissions from the at least one first lightemitting diode; and the second waveguide comprises an edge couplingcavity arranged at an edge of a body of the second waveguide andconfigured to receive emissions from the at least one second lightemitting diode.
 18. The lighting system of claim 14, wherein: the firstwaveguide comprises a first extraction feature pattern arranged at acentral portion of the first waveguide; and the second waveguidecomprises a second extraction feature pattern arranged at a peripheralportion of the second waveguide.
 19. The lighting system of claim 14,comprising at least one of the following features (i) or (ii): (i) atleast some features of the first extraction feature pattern are arrangedalong an inner face and an outer face of the first waveguide; (ii) atleast some features of the second extraction feature pattern arearranged along an inner face and an outer face of the second waveguide.20. The lighting system of claim 14, further comprising a patternedmaterial arranged between the first waveguide and the second waveguide,wherein the patterned material is configured to affect interactionbetween light emissions of the first waveguide and light emissions ofthe second waveguide.
 21. The lighting system of claim 14, furthercomprising a reflector, wherein the first waveguide is positionedbetween the reflector and the second waveguide.
 22. The lighting systemof claim 10, wherein: the at least one first LED comprises a pluralityof first LEDs of different colors and/or color temperatures to permitadjustment of color and/or color temperature of the plurality of firstLEDs; and the at least one second LED comprises a plurality of secondLEDs of different colors and/or color temperatures to permit adjustmentof color and/or color temperature of the plurality of second LEDs.